Calcium hypochlorite is a well known source of chlorine for sanitation purposes, for example, in disinfecting swimming pools. Granular calcium hypochlorite compositions having a Ca(OCl).sub.2 concentration of above about 65 percent by weight are commercially available and provide desired levels of available chlorine upon dissolution in a swimming pool. Swimming pools generally contain a variety of organic materials and suspended solids tht can impair the clarity of the water. Additionally, calcum hypochlorite compositions typically contain minor amounts of insoluble components such as calcium hydroxide and calcium carbonate that can further impair the clarity of the pool water. Any diminishment of clarity is naturally discomforting to a pool owner.
The use of aluminum sulfate hydrates with calcium hypochlorite is known. For example, U.S. Pat. No. 4,146,676 describes calcium hypochlorite particles coated with about 4 to 45 percent by weight of a low melting inorganic salt, e.g., aluminum sulfate hydrates, to reduce dusting during handling and to increase stability of calcium hypochlorite contacted with lighted cigarettes or reactive organic materials such as glycerine. U.S. Pat. No. 3,793,216 describes a calcium hypochlorite composition of substantially dry calcium hypochlorite and a sufficient amount of a hydrated inorganic salt, e.g., aluminum sulfate octadecahydrate, to provide the calcium hypochlorite composition with a water content within the range of about 3 to about 13 percent by weight. However, in these patents the levels of aluminum sulfate hydrates of these patents, i.e., above about 4 percent by weight, are in excess of the levels sufficient to achieve the flocculation of suspended solids and to enhance water clarity.